Title: Thermal and Chemical Activation of High Flyash Content Cement Based Materials

Author(s): S. Mane and b. Mobasher

Publication: Symposium Paper

Volume: 206

Issue:

Appears on pages(s): 303-323

Keywords: activators, flyash, fracture mechanism, hydration, physical and chemical activation, toughness

DOI: 10.14359/12260

Date: 4/1/2002

Abstract:
An experimental study was conducted to evaluate the mechanical properties of mortar containing flyash subjected to both thermal and chemical activation. Mortar specimens containing class F. flyash and various activators were prepared. Up to 50% by weight of cement was replaced with flyasha dn the results were compared with the control mixture. IN order to activate the gydration reafctions, additives such as sodium hydroxide (NaOH) and potassium hydroxide (KOH) were used at a rate of 2.5 % of total binder weight. Thermal activation was achieved using an autoclave curing process. Both the strengthening and toughening mechanisms were studied in compression, flexure. The fracture results are analyzed using the fracture energy method, the two -parameter facture properties remain virtually at the same level. R-Curves provide a more descriptive measure of fracture response. Autoclave curing of high flyash mortar samples results in a mrked increase in the strength but a marginal reduction in ductility.